An X-ray diagnostic apparatus for interventional radiology includes an interference preventing function of preventing a movable body, such as a C arm, from coming into contact with a subject and a couch. A medical image diagnostic system is known which alternately uses this type of X-ray diagnostic apparatus and another modality (medical diagnostic apparatus). As the second modality, a computed tomography (CT) apparatus or a magnetic resonance imaging (MRI) apparatus can be used. Where the second modality is a CT apparatus, the medical image diagnostic system is referred to as an “angio-CT apparatus” or an “angio-CT system” as well. There may be a case where this type of X-ray diagnostic apparatus and the medical image diagnostic system are used for inserting a paracentesis needle into the subject in order to take a tissue piece of a tumor and to perform an ablation treatment.
In this case, the medical image diagnostic system advances the inserted paracentesis needle to a target portion under the fluoroscopic guidance by the X-ray diagnostic apparatus, and then performs auto-positioning. By this operation, the units of the X-ray diagnostic apparatus, including the holding device and the couch, are retracted to their respective target positions, and the CT gantry of the CT apparatus is positioned. The auto-positioning is a function of automatically moving the units of the X-ray diagnostic apparatus to the target positions in response to the input of unit identification information (e.g., a number) and the operation of a trigger switch, with the target positions of the units of the X-ray diagnostic apparatus and the unit identification information being associated and registered beforehand. In the case of the angio-CT system, the CT gantry can be positioned simultaneously with the movement of the units of the X-ray diagnostic apparatus. After the CT gantry is positioned, the CT apparatus performs imaging for confirmation.
Although the medical image diagnostic system mentioned above normally causes no problem, the inventor took into consideration that the X-ray diagnostic apparatus or the CT gantry might collide with the paracentesis needle if the auto-positioning is performed without reference to the paracentesis needle projecting from the body surface of the subject. To avoid this collision, the auto-positioning is not performed, and positioning based on a manual operation is performed paying attention to the position of the paracentesis needle. Such positioning is troublesome and takes time. This problem is not limited to the case of the paracentesis needle but holds true for some kind of device projecting from the subject. In addition, the problem is not limited to the case of the medical image diagnostic system but holds true for the case of an X-ray diagnostic apparatus used alone, which temporarily retracts the holding device to its target position and then performs auto-positioning to return the holding device to the imaging position.
Accordingly, an object is to prevent collision with a device projecting from the subject and to alleviate the labor and time in positioning.